The present invention relates to solenoid control of a vehicle transmission. More specifically, the present invention relates to a combined electronic transmission control unit and solenoid module which is adaptable for onboard attachment to a transmission.
Electronically controlled automatic transmissions have become common place in today""s vehicles. Typically, these transmissions require transmission control units which monitor and control shifting patterns for the vehicles. Typically, these transmission control units are remote from the transmission and integrated with the engine control unit.
Transmission control requires hydraulic flow and pressure to be metered and routed, typically by use of solenoids. The hydraulic flow is routed by worm trails and passages in a transmission valve body. The solenoids are mounted in a relatively complex manifold which has passages and worm trails for corresponding to the worm trails in the transmission""s valve body. The solenoids are, therefore, housed integrally with a separate add-on manifold and require a complex manifold design for interacting with the transmission. Typically, the solenoids are connected to a wiring connector on the manifold which connects to a wiring harness of the vehicle. The wiring harness of the vehicle connects to a remotely mounted transmission control module of the engine control unit of the vehicle. Until recent years, it has been necessary to have the transmission control unit placed somewhere other than in the engine compartment since the transmission control unit was exposed to more heat and other harsh conditions if placed close to the transmission. Thus, typically it is necessary to have a complex wiring harness extending to the remotely mounted transmission solenoid module. Such a harness in existing designs is heavy and complex, and may lead to undesirable open circuits or electrical shorts along the wiring harness assembly. Additionally extra labor is required for installing the wiring harness.
In the motor vehicle industry today, weight has been a critical consideration in vehicles. It has been desirable to provide transmission control units which are attached to the transmission. Due to recent improvements in solid state component technology, it has become feasible to design transmission control units into the transmission. Typically, this new design implements a control unit attached to a cooling plate acting as a heat sink, which is then mounted onto a suitable portion of the transmission. A wiring harness is then utilized to connect the solenoid manifold with the control unit. Thus, even in the new design, a complex wiring harness has typically been connected between the transmission control unit and the solenoid manifold. Additionally, these new designs include a solenoid manifold which is a separate assembly from the transmission, which adds weight to the overall transmission assembly.
Therefore, it has been a goal in the art to further reduce weight and simplify transmission control in electronic transmissions today.
In accordance with the present invention, the integral cooling plate of the transmission control unit has hydraulic control solenoids mounted on the cooling plate. The plate assembly is mounted onto the transmission and is matched to a transmission valve body having xe2x80x9cworm trailxe2x80x9d passages for controlling hydraulic flow in the transmission.
Thus, the transmission control plate of the present invention reduces wiring weight and size, and simplifies control of the transmission by directly interfacing the hydraulic portion of the transmission with a transmission control unit. It also reduces size and weight, in that the solenoids are no longer required to be attached to a separate solenoid manifold. This invention also allows combining of parts which are normally separately attached to the transmission itself.
A further understanding of the present invention will be had in view of the description of the drawings and detailed description of the invention, when viewed in conjunction with the subjoined claims.